Sorry to be specific, but what exactly does it smell of?
I am sure you sould notice if the thing was so badly tanned it was going off, cos it would be runny. Other options are that this is a remnant of the tanning process, in which case you could possibly soak it out, although quite what in, I don't know, or the glue used in the manufacture.
'Proper' leatherworking glue is made out of god knows what (bones and horns, I think) and stinks to high heaven of (kind of) fish. Dunno what you would do about that.